Yes, that's right. Their mother didn't want Fred touring but their father, Verdine Adams, Sr. convinced her. Fred was playing Maurice's tubs and Maurice could see right away he had the stuff. Maurice and Verdine often had two different opinions. Maurice bought Verdine his first bass. Not really bought it for him but bought a bass and Verdine took to it like a duck to water. Oddly enough, one of the premier bassists in Chi at the time was Louis Satterfield and Verdine studied at his feet, along with classical training. Louis went on to be the trombone in the Phenix horns.
Maurice even went in and redid Fred's drum tracks at times. The first iteration(s) of EWF were a revolving door and, as you and I know, no Fred.
IMO Verdine is the best R&B bassist ever. I know many people will say JJ but JJ wasn't really an R&B bassist just like Motown wasn't really R&B. Verdine does some shit that is phenomenal. Not flashy but listen to his changes right in the middle of a bar and then a quick 3 note riff to get right back to the line. His fills are complex simplicity. He is absolutely amazing.